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A review of wireless SAW sensors 总被引:26,自引:0,他引:26
Wireless measurement systems with passive surface acoustic wave (SAW) sensors offer new and exciting perspectives for remote monitoring and control of moving parts, even in harsh environments. This review paper gives a comprehensive survey of the present state of the measurement systems and should help a designer to find the parameters required to achieve a specified accuracy or uncertainty of measurement. Delay lines and resonators have been used, and two principles have been employed: SAW one-port devices that are directly affected by the measurand and SAW two-port devices that are electrically loaded by a conventional sensor and, therefore, indirectly affected by the measurand. For radio frequency (RF) interrogation, time domain sampling (TDS) and frequency domain sampling (FDS) have been investigated theoretically and experimentally; the methods of measurement are described. For an evaluation of the effects caused by the radio interrogation, we discuss the errors caused by noise, interference, bandwidth, manufacturing, and hardware tuning. The system parameters, distance range, and measurement uncertainty are given numerically for actual applications. Combinations of SAW sensors and special signal processing techniques to enhance accuracy, dynamic range, read out distance, and measurement repetition rate (measurement bandwidth) are presented. In conclusion, an overview of SAW sensor applications is given. 相似文献
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Zhu J Emanetoglu NW Lu Y Kosinski JA Pastore RA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2001,48(5):1383-1388
Tunable surface acoustic wave (SAW) filters (TSF) have been widely used in the wireless telecommunication systems. A prototype of multi-IDT (interdigital transducer) input TSF has been developed. The device consists of 11 IDTs paralleled in the SAW propagation path. Different SAW filter configurations are realized by selecting or combining various IDTs, resulting in the tunability of both center frequency and 3 dB bandwidth. The center frequencies of the SAW filter range from 126.8 to 199.1 MHz; the 3 dB bandwidths range from 15.2 to 58.9 MHz. Impedance weighting methods have been applied. The passband ripple has been reduced from 6.44 to 1.37 dB after resistance weighting 相似文献
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Measurements of the phase noise modulation imparted on UHF carriers by surface-acoustic-wave (SAW) filters and resonators have been made using an HP 3047 spectrum analyzer. Three different types of SAW phase noise were observed. One type can be explained by temperature fluctuations. It is characterized by a spectral density of phase fluctuations which decreases as 1/f(2). The predominant noise mechanism in most SAW devices has a 1/f spectral density. The source of this noise is unknown, but it appears to be associated with both acoustic propagation and transduction. In filters fabricated on lithium niobate substrates, a third noise mechanism is evidenced. This mechanism produces nonstationary noise bursts that appear to originate in the transducer region. Experiments have been carried out on substrate materials, transducer metallizations, and over acoustic path lengths. The means by which low-frequency fluctuations are mixed to the carrier frequency have been studied. 相似文献
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Rukhlenko AS 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(10):1930-1935
It has been demonstrated by several authors that the well-known weighted least squares (WLS) approximation can be equiripple if a suitable weighting function is applied. In the present paper, the WLS algorithm is generalized to SAW filter synthesis with prescribed magnitude and phase specifications. Several weighting techniques producing quasi-equiripple designs are presented. The frequency sampling technique is used for SAW filter frequency response approximation to reduce the number of optimized variables. The WLS algorithm rapidly converges both for linear and nonlinear phase SAW filters. Typically, no more than 5-10 iterations are required to obtain the WLS solution to accuracy better than 0.5-1 dB in the stopband when compared with the optimum Chebyshev approximation. Moreover, it is shown that the WLS technique can be effectively applied for second-order effect compensation. 相似文献
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Tobar ME Hartnett JG Ivanov EN Cros D Bilski P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(10):1349-1355
A dual-mode, sapphire-loaded cavity (SLC) resonator has been designed and optimized with the aid of finite element software. The resonance frequency was designed to be near the frequency of a Cs atomic frequency standard. Experimental tests are shown to agree very well with calculations. The difference frequency of two differently polarized modes is shown to be a highly sensitive temperature sensor in the 50 to 80 K temperature range. We show that an oscillator based on this resonator has the potential to operate with fractional frequency instability below 10/sup -14/ for measurement times of 1 to 100 seconds. This is sufficient to operate an atomic clock at the quantum projection noise limit. 相似文献
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《IEEE transactions on instrumentation and measurement》1980,29(2):105-113
This paper gives a closed-form solution for the minimum error one can expect from a linear prediction filter applied to a clock for which the fractional frequency power spectrum consists of white noise and the integral of white noise. Measurement error is also included. Expressing the problem as a Wiener filter rather than a Kalman filter simplifies the solution. The Kalman matrices in the Wiener representation are diagonal. This permits one to derive the optimum linear filter directly from the spectrum. Since the spectrum of flicker noise is not rational, no closed-form Wiener solution is possible. It is demonstrated, however, that all error terms including flicker can be taken into account by a technique of numerical integration in the frequency domain. The technique is valid for any filter for which the integrals, and consequently the error, do not diverge. It is shown that every first-order prediction filter with two poles must have the form of the Wiener filter, except for the position of the poles. A special case of this filter is shown to be the first-order exponential predictive filter. The error can be expressed in powers of the prediction time, with four coefficients, one for each spectral term. The values of these coefficients were calculated and plotted for the first-order exponential filter. These coefficients were used to calculate the error for three clocks. The results are plotted for prediction times of two hours and one day. 相似文献
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Shmaliy YS Arceo-Miquel L 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(10):2131-2139
This paper addresses an unbiased p-step predictive finite impulse response (FIR) filter of the local clock K-degree time interval error (TIE) polynomial model with applications to the global positioning system (GPS)-based clock synchronization. Generic coefficients are derived for a 2-parameter family of the polynomial filter gains. A generalization is provided for the p-step linear (ramp) gain allowing for close to optimal predictive filtering of the TIE. Basic holdover algorithms are discussed along with their most critical properties. Efficiency of the proposed filter in holdover is demonstrated by simulation and in real applications to GPS-based (sawtooth and sawtoothless) measurements of the TIE of a crystal clock. 相似文献
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Routray A. Pradhan A.K. Rao K.P. 《IEEE transactions on instrumentation and measurement》2002,51(3):469-479
A simple and novel approach in the design of an extended Kalman filter (EKF) for the measurement of power system frequency has been presented in this paper. The design principles and the validity of the model have been outlined. The performance of this filter has been compared with some of the existing methods for estimating the frequency of a signal under noisy conditions. The feasibility of the proposed filter has been tested in the laboratory under worst-case measurement and network conditions, which might occur in a typical power system. Also, the proof of the stability for the proposed filter has been discussed for a single sinusoid. It has been found that the proposed algorithm is suitable for real-time applications especially when the frequency changes are abrupt and the signal is corrupted with noise and other disturbances due to harmonics 相似文献
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M. A. M. Cavaco M. E. Benedet L. R. Neto 《International Journal of Thermophysics》2011,32(11-12):2343-2350
In several applications in the field of metrology, the direct connection of the sensor element with the respective signal-processing unit of the measurement system is not trivial. It can be mentioned, as an example, the measurement of hot points in electric power substations because of the high electrical potential. To solve that problem, two alternatives were studied, one using active surface acoustic wave (SAW) sensors and other using passive SAW tags. For the passive sensor, a SAW radio-frequency identification (RFID) temperature detector was used. That technology is widely applied for typical transport identification (grain transportation, road traffic control), but its application in the field of metrology is innovative. The variation in temperature makes an alteration in the characteristics of the piezoelectric material of the SAW matrix, changing mostly the resonance frequency. Using SAW?CRFID, the problem of measuring temperature basically is directed to the identification of the frequency of resonance of the SAW. The use of active SAW sensors has been demonstrated to be much more satisfactory for the solution of such a problem because of the limitation in the range of the passive sensors. 相似文献
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Kadota M Kando H 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(4):464-469
It was previously reported that a Rayleigh wave propagating on a zinc oxide film (ZnO)/ST-cut 35 degrees X propagation quartz substrate structure has the characteristics of an excellent temperature coefficient of frequency (TCF) and a large electromechanical coupling factor k(s). This substrate was applied to various intermediate-frequency (IF) stage filters. During the filter development, it was clarified that a spurious response due to the Love wave was generated. In this study, a new quartz substrate has been developed with a specific cut and propagation angle, that has the same values of the TCF and the coupling factor as the above-mentioned ones. In addition, it does not have the spurious response due to the Love wave. The combination of this specific-cut-angle quartz and ZnO film has been applied to IF filters for wideband code division multiple access (W-CDMA) and narrow-band CDMA (N-CDMA) systems. The insertion losses of their IF filters were 3-5 dB better and their TCF was superior (deltaf/f = 0.37 ppm/degrees C: one-third) compared with the conventional surface acoustic wave (SAW) filters. 相似文献
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Bennès J Alzuaga S Chérioux F Ballandras S Vairac P Manceau JF Bastien F 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(10):2146-2151
The capability to accurately handle liquids in small volumes is a key point for the development of lab-on-chip devices. In this paper, we investigate an application of surface acoustic waves (SAW) for positioning micro-droplets. A SAW device based on a 2 x 2 matrix of inter-digital transducers (IDTs) has been fabricated on a (YXI)/128 degrees LiNbO3 substrate, which implies displacement and detection in two dimensions of droplets atop a flat surface. Each IDT operates at a given frequency, allowing for an easy addressing of the active channel. Furthermore, very low cross-talk effects were observed as no frequency mixing arose in our device. Continuous as well as pulsed excitations of the IDTs have been studied, yielding, respectively, continuous and step-by-step droplet displacement modes. In addition, we also have used these two excitation types to control the velocity and the position of the droplets. We also have developed a theoretical analysis of the detection mode, which has been validated by experimental assessment. 相似文献
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《IEEE transactions on instrumentation and measurement》2009,58(6):1833-1840
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Shmaliy YS 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(5):862-870
An unbiased finite impulse response (FIR) filter is proposed to estimate the time-interval error (TIE) K-degree polynomial model of a local clock in global positioning system (GPS)-based timekeeping in the presence of noise that is not obligatory Gaussian. Generic coefficients for the unbiased FIRs are derived. The low-degree FIRs and noise power gains are given. An estimation algorithm is proposed and examined for the TIE measurements of a crystal clock in the presence of the uniformly distributed sawtooth noise induced by the multichannel GPS timing receiver. Based upon this algorithm, we show that the unbiased FIR estimates are consistent with the reference (rubidium) measurements and fit them better than the standard Kalman filter. 相似文献
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目的 为了提高声表面波(Surface acoustic wave,SAW)温度传感器的测量精度,设计一种基于PSO-ESPRIT算法的高精度SAW温度传感器解调方法。方法 以ESPRIT谱估计方法为基础,把Hankel矩阵的时间窗长度与计算噪声方差时的K值作为粒子群优化(Particle swarm optimization, PSO)算法的输入变量,并以频率估计标准差作为粒子的适应度函数,利用PSO对ESPRIT算法中的参数进行优化,以改善频率估计精度,从而提高SAW回波信号频率估计的分辨率,实现SAW温度传感器的高精度解调。结果 仿真和实验结果表明,所设计的方法与其他谱估计算法相比,其对SAW回波信号估计的频率误差最小,标准差小于0.66kHz。把设计的算法用于SAW温度传感器的温度解调,得到的温度值与实际温度的误差小于0.4℃。结论 测试结果说明,设计的温度解调方法提高了SAW回波信号频率解调精度,可用于SAW温度传感器的解调,实现了对食品包装储运过程中温度的实时监测。 相似文献
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V. A. Bazhenov E. S. Dekhtyaryuk T. G. Zakharchenko O. A. Luk'yanchenko V. F. Imdukh 《Strength of Materials》2000,32(2):178-186
We consider some problems related to the analysis of the modes of forced vibrations of elastic plates induced by random narrow-band
excitations. The investigation of nonlinear vibrations of a plate is performed within the framework of a reduced discrete
model constructed by using the Hamilton variational principle, finite-element methods, and generalized coordinates. To study
the dynamical state of the analyzed structure, we perform numerical simulation of the vibrations induced by a particular realization
of narrow-band excitations. Each realization of random narrow-band excitations is obtained with the help of a shaping filter
of the second order and describes harmonic oscillations with slowly varying amplitude and phase. We also consider the scenarios
of transitions between different modes of vibrations of the plate and estimate the time of its residence in different dynamical
states.
Kiev National University of Civil Building and Architecture, Kiev, Ukraine. Translated from Problemy Prochnosti, No. 2, pp.
105–117, March–April, 2000. 相似文献
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Haofeng L Rui J Weilong L Chen C Xinyu L 《Journal of nanoscience and nanotechnology》2010,10(11):7258-7261
A high frequency Surface Acoustic Wave (SAW) filter which is the key point of the SAW sensor is made by MEMS technology. The SAW filter used for sensors needs to have the factors of high frequency, low loss and high quality factor. In order to satisfy the performance of the factors, the SAW delay lines of Electrode Wave Control Single Phase Unidirectional Transducer (EWC/SPUDT) are used in the filter. This transducer can be considered as the networks of connection of some units of IDTs and the loss of device can be effectively reduced. Based on the Coupling of Modes (COM) theory and equivalent circuit modal, the mixed matrix (P matrix) of the transducers can be deduced, and further, the response of the delay lines can be obtained. According to the calculated results, a mask layout is made. Then the SAW delay line is completed and found to agree with the theoretical simulation. Its center frequency is 503 MHz and insertion loss is low enough for use of sensors. 相似文献